Categories
Advanced

The weather balloon

A circle with three red tangents. The tangency points are marked red. Prove that the yellow triangle is isosceles.

Categories
Intermediate

A square deal II

A regular hexagon and a square share a vertex. What’s green : red?

Categories
Beginner

The antipodes

Two squares share a vertex. Four other vertices are connected as shown. Prove that the red points are collinear.